I use a sbc device with emulators now a days. It’s the perfect “pick up and put down” situation for me. I’d really recommend looking into it especially for quality of life things like save states and being able to pick up where you left off exactly.
As for deciding what platforms to play, my biggest advice is looking at how many buttons a controller has. I don’t see people talk about this a lot, but when I’m looking to play a simple game, my first thought is “how many buttons do I feel like using?”
With this thought in my mind I’ve been gravitating towards things like GBA, SNES, N64, and when I want something a little more complex, Ps1 or Dreamcast.